Preparation

Drain and rinse the soaked beans and heat the oven to 350.

Heat the oil in a 6-quart Dutch oven or other large, heavy pot over medium-high until hot but not smoking. Add the chicken thighs and brown well, 4 to 6 minutes. Remove the thighs, add the sausage to pot and brown well, another 4 to 6 minutes. Remove the sausage. Add the onion, bell pepper and celery and sauté, stirring occasionally, until tender, 5 to 7 minutes.

Add the garlic and sauté, stirring frequently, 1 minute. Add back the thighs and sausage along with the beans, filé powder if using, red pepper flakes, salt and pepper and enough water to cover. Stir well and bring the mixture to a simmer.

Cover and transfer the pot to the oven and bake until the beans are tender, 2 1/2 to 3 hours, checking every half-hour or so after the first hour and adding water as needed if all the liquid has been absorbed.